The relationship between
total
motile sperm count and pregnancy
rate after intrauterine insemination

Tooba Mehrannia1

ABSTRACT

Objective: To determine the
relationship between the total motile sperm count and the success of IUI
treatment cycles with postwashed husband spermatozoa in couples with
infertility in a large patient population.

Main outcome measure(s): To assess
the significance of prognostic factors including a womanís age, duration
of infertility, diagnoses, use of ovulation induction and sperm parameters
for predicting the outcomes of clinical pregnancy after the first cycle of
IUI.

Results: The pregnancy rate per cycle
was 18.2% (150/824). Postwashed semen parameters including total motile
sperm count >10◊106,motility >50%. There was a trend toward an increased
success rate with increased total motile Sperm count.

Conclusion: Our finding suggest that
a final postwashed total motile sperm count used for IUI may be considered
predictive of the success for pregnancy.

*
Received for Publication: January 7, 2006
* Accepted: April 26, 2006

INTRODUCTION

Intrauterine insemination (IUI) is commonly
used to treat infertile couples with varying etiologies of infertility,
such as male-factor infertility

1 or unexplained
infertility.2It can overcome the problems
associated with husbandís inability to ejaculate inside the womanís vagina
due to impotence, premature ejaculation or other medical conditions.3
Controlled ovarian stimulation has been shown to have an
additive effect on the pregnancy rate when combined with IUI for
unexplained infertility.2Intrauterine insemination
is used if timing of exposure to sperm is controlled and spermatozoa are
placed in the uterine cavity.4The beneficial effect
of controlled ovarian stimulation may be lost if male has low sperm
counts.2,5,6

The purpose of this study was to evaluate
outcomes of treatment from a large database of infertile couples and
determine prognostic factors for achieving a pregnancy with IUI. The
effect of the number of motile sperm on the outcomes of IUI, controlled
ovarian stimulation combined with IUI, has been studied and interpreted
here.

PATIENTS AND METHODS

One thousand eight hundred forty one
therapeutic intrauterine insemination (IUI) were done for eight hundred
twenty four women with age of 20-45 years. All patients were evaluated by
physicians in the Academic University Hospital and had infertility,
defined by >2 year of unprotected intercourse without conception.
This study was limited to the first cycle that was performed for every
couple.

A standardized infertility evaluation was
performed on all couples that included at least one semen analysis, a
histrosalpingogram and some documentation of ovulation most commonly by a
day 21 progesterone level. Other infertility evaluation including
postcoital test, endometrial biopsies and laparoscopies were not performed
in all couples but rather, were performed at discretion of the physician
after consultation with the couple.

Women were categorized into the following
groups of infertility diagnoses on the evaluation: anovulation, tubal
disease (defined as any abnormality of one or both fallopian tubes or a
history of any tubal surgery), or no abnormality if all tests were normal.

All patients had ovarian stimulation with a
combination of clomiphen citrate (100mg from 3rd days of menstrual cycle)
and hmg (75IU IM) beginning at 8th day of menstruation, which was adjusted
with follicular development monitoring by vaginal ultrasound. When at
least one leading follicular diameter was 18mm, 10000IU IM hcg was
administered.

IUIs were performed 36 hours after the
administration of hcg. Male factor infertility was not strictly defined
but was assessed by analyzing the number of motile sperm in the ejaculate.
Couples were considered to be candidates for treatment by IUI if the woman
was ovulatory and had at least one open fallopian tube and motile sperm
were present in the maleís ejaculate. All treatment decisions were made by
a reproductive endocrinology staff physician after consulting with the
couple.

All couples were requested to abstain from
intercourse for 2-7 days before IUI semen samples were obtained at the
laboratory. Immediately after Liquefaction, a drop of the well mixed
specimen was placed on a clean and prewarmed glass slide at 37

oc,
covered with a coverslip and left for a few minutes.

The preparation was examined under a
magnification of both ◊10 and ◊40 objectives. The motility assessment was
done according to World Health Organization guidelines. In at least 10
separate randomly selected high-power fields. The motility was recorded.
Spermatozoa were prepared by the swim-up technique. Samples were diluted
in Hamís F10 medium with 5% human serum albumin (HAS) and centrifuged for
three minutes (300◊g). The pellets were resuspended in 1ml of medium and
centrifuged for three minutes at 300◊g and then were left at 37

oc
for 30 to 60 minutes in humidified incubator (5%CO2). The postprocessing
volume, sperm concentration and motility were obtained and recorded. All
variables were separately tested to determine their significance in
predicting the occurrence of clinical pregnancy. For these evaluations, x2
analysis was used for categorical variable. Significant differences were
determined at p<0.05 levels.

RESULTS

The characteristics of patients treated by
IUI are listed. Overall clinical pregnancy rate was 18.2%. The mean age of
female was 29.3(range 20-40). The majority of the pregnancies were
achieved in 25-29 years old (20.8%); Table-I.

Data showed that although the differences
between pregnancy rate and the kind of infertility were statistically
insignificant, the highest rate of pregnancy was observed in patients with
unexplained infertility (Table-II). Duration of infertility didnít
influence pregnancy rate, but the pregnancy rate according to infertility
duration <5years, 5-10 years and 10-15 years were observed in patients
96(18.1%), 42(21.3%), 12(17.8%) respectively. With >15 years infertility
no pregnancy occurred. We examined the total motile sperm count (TMSC) in
both ejaculate and in the inseminate for the first IUI cycle. We observed
a threshold effect with the lowest pregnancy rate found in the lowest TMSC.
The pregnancy rate was significantly increased with high number of
inseminated motile sperm of over 10million/ml (Table-III). Our results
demonstrated that the percentage of normal forms postwashed sperms >50
was related with pregnancy in 150 cases; and pregnancy wasnít observed
with sperm motility less than 50% in postwashed sperm analysis (p<0.001).

DISCUSSION

This study sought to determine important and
independent variables for predicting pregnancy after standard infertility
treatments by controlling for all other variables. We found that several
patientsívariables significantly predicted pregnancy after IUI. Younger
female age, a history of pregnancy, the use of clomiphene citrate for
controlled ovarian hyperstimulation and average total motile sperm count
>10 million were all independent-predi- ctors in clinical pregnancy after
IUI treatment.

Duration of infertility and infertility
diagnoses in the woman were not significant predictors of pregnancy after
IUI. Increasing female age resulted in reduced chances for pregnancy after
IUI. Pregnancy rate following IUI performed in woman over the age of
40-year-old are less.

Many investigators have confirmed a
significantly lower pregnancy rate per cycle in women over the age of 35
years (7 to 10%) compared with younger ones (15 to 23%).

7-10Some studies showed the outcome of IUI treatment was
adversely affected if the femaleís age was >39 years.11
No pregnancies have been observed in women 40 years or older but the age
did not have a significant effects either.12

In our study, an advanced female age has not
been found to affect the pregnancy rate in controlled ovarian
hyperstimulation (COH)/IUI treatment. The duration of infertility has been
shown to be a prognostic factor for live births among untreated subfertile
couples in several studies. After two to four years of infertility the
likelihood of a live birth begin to decrease.

13

In controlled ovarian hyperstimulation and
IUI therapy, outcome will be significantly impaired after 3 to 8 years of
infertility;

7but there are studies in which the
duration of infertility has not been shown to affect the pregnancy rate.14Our finding confirmed similar results. Controlled ovarian
hyperstimulation together with IUI is widely used for the treatment of
subfertility, particularly for couples with unexplained infertility,
male-factor infertility or mild endometriosis.8,15,16

In our study, although the difference of
pregnancy rate in categories of subfertility wasnít statically
significant, the maximum pregnancy rates was observed in patients with
unexplained infertility (30.5%). The average total motile sperm count
proved to be a useful predictor of the chance for pregnancy after IUI as
compared with individual seminal fluid analysis results. The variability
in individual semen analysis results is well known, as is the significant
overlap in results when comparing fertile with infertile men.

17

We observed a threshold effect for the
average total motile sperm count (TMSC). When the average TMSC was <10
million, pregnancy rates were very low after IUI whether or not controlled
ovarian hyperstimulation was performed in the woman. IUI pregnancy rates
reached a plateau with no further increases in the pregnancy rate noted at
higher values.

When the average TMSC was above 30 million,
we noted higher pregnancy rates when controlled ovarian hyperstimulation
was used in conjunction with the IUI cycle as compared with natural cycle
IUI .

Most studies evaluating the effect of semen
parameters on outcomes of IUI have concluded that couples with a
male-factor for infertility have low pregnancy rates after IUI.

10,11,18-22Nearly all studies have confirmed that the addition of
controlled ovarian stimulation does not improve the pregnancy rate of IUI
in couples with severe male-factor infer- tility.2,5,6,23,25
Differences in outcome of various studies are likely related to how the
male-factor infertility is defined and severity of the male-factor.
Several studies have concluded that IUI is useful in male-factor patients
from the trial.5,26,27 Many of the men in our study
with average TMSC >10million would still be defined as having male-factor
infertility, based on World Health Organization criterion. In conclusion,
postwash semen quality was the most important factor for predication of
successful pregnancy in this study.